This invention relates to hepatitis B and, more particularly, to a vaccine for hepatitis B and to a method for purifying hepatitis B antigen for use as a vaccine.
Hepatitis B is one of two types of viral hepatitis which results in a systemic infection with the principal pathologic changes occurring in the liver. This disease affects mainly adults and is maintained chiefly by transfer of infection from long term carriers of the virus. Usual methods of spread are by blood transfusion, contaminated needles and syringes, through skin breached by cuts or scratches, by unsterilized dental instruments as well as by saliva, venereal contact or exposure to aerosolized infected blood.
The incubation period of type B hepatitis is relatively long: from 6 weeks to 6 months may elapse between infection and the onset of clinical symptoms. The illness usually begins with fatigue and anorexia, sometimes accompanied by myalgia and abdominal discomfort. Later jaundice, dark urine, light stools and tender hepatomegaly may appear. In some cases, the onset may be rapid, with appearance of jaundice early in association with fever, chills and leukocytosis. In other cases, jaundice may never be recognized and the patient may be aware only of a "flu-like" illness. It is estimated that the majority of hepatitis infections result in a mild, anicteric illness.
Although qualitatively similar to viral hepatitis A, the disease is readily diagnosed by the appearance of the Australia antigen particles, now designated by HB.sub.s Ag (surface antigen), in the blood or other clinical specimens (saliva, urine, bile, feces). There occurs in the blood of infected individuals a relatively large population (10.sup.14 -10.sup.15 /ml.) of spherical particles. The particles are 18-22 nm in diameter and have the same antigenic determinants as the surface of the 42 nm Dane particle which may be the virus of hepatitis B, now designated HBV.
U.S. Pat. No. 3,735,004 indicates that boiled infectious serum was used to vaccinate children with resulting antibody to HB.sub.s Ag (anti-HB.sub.s) and that such serum provided protection against challenge. The dose of boiled serum used was equivalent to about 1 .times. 10.sup.12 HB.sub.s particles. The recipients of such serum did not develop clinical or bio chemical disease. This serum, however, is not suitable for use as a vaccine, because of its impure nature, its lack of reproducibility and its non-quantitation.
It is, accordingly, an object of the present invention to provide a vaccine for hepatitis B. Another object is to purify hepatitis B antigen by removing extraneous undesirable proteins and/or antigens. A further object is to provide a method for removing extraneous undesirable proteins or antigens from hepatitis B antigen. Yet another object is to provide pharmaceutical preparations to administer the purified hepatitis B antigen as a vaccine. These and other objects of the present invention will be apparent from the following description.